One of the interesting possibilities for the Fermi Paradox is the fact that we've wiped out the readily accessible deposits of iron, coal, oil, etc. A second go at the industrial revolution would be much harder, if we regressed that far.
Might depend how long it takes: because rust is porous and friable, rusting iron should eventually degrade to nothing, and the rust would be difficult to re-concentrate then reduce back to iron.
Possibly an analogous situation is the history of steel in Japan and their efforts to extract iron from sand, since they don't have significant iron ore to mine on their island.
A city decayed to rust is going to be a thin layer of iron spread out over miles with some hot spots like where a building once stood (but presumably without a map of the city in this distant future scenario), but there won't be a vein of concentrated ore. Distributed rust can definitely be turned back into pure iron but the energy requirements are going to be substantially higher to do so since you're going to have to sift through much more material to collect it, more material to separate and concentrate it, more material to smelt off, and your operations will have to be more mobile to retrieve it over a larger area. That's why I think retrieving iron from our society will be more like extracting iron from ironsands (2-20% iron), and it will have similar effects on that subsequent society that sits between us now and some future point where geology has re-supplied it to the surface millions of years from now.
FWIW those are the ratios for the oxides themselves but the formations are not necessarily huge piles of pure oxides, if you go a bit lower to the "sources" section the lowest-concentrated formations viable for exploitation are
> Banded iron formations (BIFs) are sedimentary rocks containing more than 15% iron composed predominantly of thinly bedded iron minerals and silica (as quartz).
However that's only for post-industrial societies, at least if you have alternatives, as it requires churning through ridiculous amounts of materials.
When you don't have alternatives the ironsand article (which would be used in places with no good or accessible ore deposits e.g. japan, famously) quotes
> Sand used for mining typically had anywhere from 19% magnetite to as low as 2%.
though much like gold panning the ironsand would be sluice-separated to a concentration of 30-50% before it was further processed.
Most ironsands deposits are not considered financially exploitable to this day though, with the exception of NZ's where the iconic "black sand" beaches of north island are extremely rich in magnetite (up to 40%).
They're concentrated rust mixed with rocks, otherwise it's not economically viable to extract.
Like, iron is ridiculously common, relatively speaking: on earth as a whole it's more common than oxygen, for the crust it ranks 4th at 5% by mass, meaning if you went at it randomly you'd need to sift through 20kg of materials to get 1kg of iron.
Currently, we exploit formations as low as 15% iron (banded iron formations / taconite), that's the lower limit of the economically feasible, and those results in absolutely enormous amounts of tailings (waste materials).
Pre-industrialisation, unless you had no other choice (e.g. only had ironsands to work with) you really wanted to exploit natural (or "direct-shipping") ores, in the 60~70% range, the extraction is way too much work otherwise.
Fortunately, despite millions of tons of production every year, we are nowhere near using up the ore.
Producing 1kg of charcoal requires 3-4kg of wood. (Producing the 900°C for the process is an exercise for the reader.) (https://www.fao.org/3/y4450e/y4450e11.htm)
Coal didn’t overtake charcoal for smelting iron in the US until the latter half of the 19th century, well after the first industrial revolution.
Melting down scrap iron is one of the main sources of steel in the US, and that is done straight with electricity in arc furnaces.
Coal accelerated the second industrial Revolution, but it was not essential. Far more important for enabling the first industrial Revolution was some of the early scientific knowledge about steam and pressure, such as the work of Robert Boyle, a lot of that based on a sort of reaction to the classics that had been revived in the Renaissance. The biggest argument for coal is indirectly in that it helped the viability of British society (after the island had most its tree cut down over the previous 500 years) which played an important role in the Scientific Revolution (Robert Boyle was Anglo-Irish)… although by the time Britain was playing an important role, the scientific Revolution was already underway on the mainland of Europe. As long as our books are not all destroyed, I think we’d have no problem bootstrapping from charcoal the second time around.
(I think a lot about long term data storage… writing in stone or fired clay still seems like one of the best methods for writing that needs to last 10,000 years… it was, after all, preserved Greco-Roman classics that enabled the renaissance and therefore the scientific Revolution.)
Finding out we've got a hard to replace left-pad module somewhere far up the tech tree wouldn't be fun.
And no, you don't need such sophistication for storing useful amounts of hydrogen. Storing large amounts of hydrogen (in this case, also mixed with poisonous CO) was solved in the beginning of the 19th Century (well, late 18th century) in Britain and Germany by using very large near-atmospheric storage vessels called Gas Holders: https://en.wikipedia.org/wiki/Gas_holder
Salt caverns can also be used for greater volumes, i.e. for seasonal storage, as are already used for hydrogen storage in a few places in the US and elsewhere. https://en.wikipedia.org/wiki/Underground_hydrogen_storage
https://www.businessinsider.com/everything-you-need-to-know-...
Asteroid hits. Wipes out almost all life. A million years later, the biomass around us will have all been converted to a black ooze (oil), covered by millennia of rock, sediment, and tectonic plates. Eventually future civilized beings who plunder the Earth for our biomass that has been converted to oil and coal discover uncanny hard-to-explain remnants of a past civilization of, get this, bipedal animals.
Oil forms when sea plankton and algae are buried and exposed to high pressures and heat. Coal forms when dead plant material protected somehow from biodegredation (say by mud) forms peat and is then buried, and exposed to high pressures and heat.
I was also surprised to learn that the inabality of fungus and bacteria to degrade lignin is unlikely to have been a key driver of coal formation during the Carboniferous period, instead it was "a unique combination of everwet tropical conditions and extensive depositional systems during the assembly of Pangea".
Source: https://www.semanticscholar.org/paper/Delayed-fungal-evoluti...
(To redirect Chixculub would require a MUCH larger capability, probably on the order of 10 million tons in orbit, but that's possible with a fleet of large reusable rockets capable of getting the cost to orbit down to around $10/kg, or equivalent development of in-space resource utilization capacity.)
For greatest success I think there would need to be two but probably not many more than two major efforts going on simulatneously, in much the same way that CMS and ATLAS experiments at CERN were independently looking for the Higgs. If one fails for some unforseen technical reason, the other might not if they took a different approach.
Well, yes. It's not fair to the dinosaurs, I admit. They hardly had a chance to develop language and mathematics. They were still too busy ripping each other's faces off. And not having opposable thumbs, of course, really put a damper on technological development. Maybe in a another million years things would have been different, but the asteroid had a different idea.
We, on the other hand, are at least on the precipice of the capability to divert asteroids. Hopefully we don't get an asteroid visit too soon.
Diverting an asteroid, however, is not evolution.
If they got further than us, tried to capture an asteroid and mine it, could they have wiped themselves out without leaving behind technosignatures that would still be visible?
Some real geologists explored the idea (someone could find the paper and subsequent news articles) and I think the conclusion was that on geological time periods, there might not be much left for us to find.
The rate at which we're accumulating change compared to geological record is also a strong argument against, although they argue limitations in current dating methods reducing how much can be said with certainty about prior epochs.
While there is precious little reason and evidence to believe a priori in a previous advanced dino civ, there are studies that could be done on sediment data that'd lend more certainty (such as looking for unusually rapid metal production).
> Anthropocene layer in ocean sediment will be abrupt and multi-variate, consisting of seemingly concurrent-specific peaks in multiple geochemical proxies, biomarkers, elemental composition and mineralogy. It will likely demarcate a clear transition of faunal taxa prior to the event compared with afterwards. Most of the individual markers will not be unique in the context of Earth history as we demonstrate below, but the combination of tracers may be. However, we speculate that some specific tracers that would be unique, specifically persistent synthetic molecules, plastics and (potentially) very long-lived radioactive fallout in the event of nuclear catastrophe. Absent those markers, the uniqueness of the event may well be seen in the multitude of relatively independent fingerprints as opposed to a coherent set of changes associated with a single geophysical cause.
My opinion is this ultimately boils down to how hard human level intelligence is to evolve, which is why the hypothesis is interesting in the context of the Fermi Paradox. Intelligence might be extremely difficult to evolve, it might require an unusual background environment set of condition or just might not be that useful in general.
I doubt the dinosaurs shuttled away or buried all their geo-engineering marks.
There's no good way to read just those strips, but it starts here:
To make things worse for a hypothetical advanced dinosaur species, if they were at the point they could capture an asteroid, they would be roughly equivalent or better with us but we could survive an asteroid extinction event just fine. Society as we know it perhaps wouldn't survive but an event that could genuinely end us as a species would need to be exceedingly destructive or long term. Otherwise the remnants will rebuild, give or take a couple 10s of thousands of years, which is basically nothing on the timescales we're thinking about here.
Film-makers would use stop-motion techniques to depict battles between Fordusprefectops and Chevroletcamaro-Rex whilst their own early ancestors look on, clad in loincloths and bras made from footwell mats.
Industrialization without fossil fuels would scale much more slowly with wood being used at first and then probably crops being grown for energy (biofuel). Once we figured out electricity we'd have large scale hydropower and wind power. Then we'd figure out either photovoltaics or nuclear fission, at which point we'd be off to the races. My guess is we'd be almost 100% nuclear and hydro powered right now with use of photovoltaics growing.
Stable power grids would probably take longer to emerge, but we figured out simple rechargeable batteries (lead-acid) fairly early. People would probably have banks of these in their homes to power minimal lighting and things like radios, TVs, etc. at night and run their appliances at specified times when the grid was at high power. You'd probably see a food system less dependent on refrigeration until stable grids emerged.
On extremely long historical timescales I suppose depletion of other elements is possible, but things like iron are incredibly common in Earth's crust. I'd be concerned more about rare elements.
It’s odd to me that we don’t see this specific point discussed all that much. Sure, it comes up here and there now and then, but I think it deserves an extended discussion. My understanding, based on what I’ve read about this implication, is that we as a human species only get one chance to evolve beyond the gravity well of our planet. If we fuck this up, and by all accounts it looks like we are, we will be condemned to extinction on Earth.
We stop mining coal when it is no longer economical to do so, not when the mine is entirely depleted. There's a bunch of coal at or near the surface and will be for quite some time.
The same goes for Oil. We extract that which is easiest to extract and fraction into the products we desire, preferring to leave things like the energy intensive and more polluting "Tar Sands" behind.
Constraints don't always lead to bad outcomes.
Japan developed their hugely overdone turned-steel technique because the ore they had to work with was so bad: hammering the garbage out was the only way to get the quality of the steel itself into acceptable levels. As a result, Japanese smiths developed something very close to what we'd now call layered steel.
European swordsmiths (think: Toledo) had access to higher-grade ore, and as a result never needed to develop techniques to work around fundamental problems with their source material.
The world is (imho) a better place because Japan has bad iron ore. If that wasn't our reality, we would never have guessed it.
That's not to say that European swords were better than Japanese swords in every way. This is one of many, many factors. And I'm sure there were plenty of crappy longswords at the time (and crappy katans), so you kind of also have to decide if you're comparing the best examples, average examples, or low quality items as well. The skill of the wielder is also important. If you're throwing out a bunch of random soldiers without a ton of training and giving them a sword, you might want to give them something they're less likely to break. My understanding that is there was a period in Japan where only samurai were allowed to carry swords (if my reading is to be believed), who were generally very skilled. They would probably know how to avoid putting their blade in situations where it would be prone to breaking.
And Japanese traditional Japanese sword making techniques are extremely impressive and interesting to read about given the materials that were available at the time.
My understanding is that historically the best steels were made in India/Southern-India where wootz steel comes from and that for more than 2000 years the rest of the world was almost bargain tier in comparison. To the degree that samples of wootz steel were brought back to Europe even in the 18th century in an attempt to replicate the process.
I'm only an amateur metalworker though so I hope someone more knowledgeable can correct any errors.
All the new land and end of the swamps is apparently the result of hundreds of years of iron ore mining in the nearby mountains. So even with primitive means and shitty ore, if you need the material and go at it for centuries, you can achieve substantial results. Not to mention reclaim some land as a result. :)
Also in related (but much more recent development) there were coal mines in Japan mining from under the seabed via tiny islands!
Hashima is the most extreme example, basically a piece of barely dry rock that has been converted to a concrete city housing many thousands of workers and their families: https://en.wikipedia.org/wiki/Hashima_Island
But there were other such mines, some of the local ones even connected to Hashima via the underground works!
And the point isn't about that. The point is that the constraint (bad ore quality) forced the Japanese to get better at metalworking. Resource constraints aren't as bad as we think, because we're used to making things without those constraints. But our descendants, having always had those constraints, will find better ways of solving them than we can think of.
Even in Europe, a large part of the armies were peasants with whatever comes to hand. Their resource constraint on metals wasn't the ore, but the availability of the enormous quantities of wood required to process it.
Every Samurai had at least two swords. So at least a million swords. Let's say a sword weighs 1Kg, that's 1000 tonnes of steel. So probably not enough for a battleship, but maybe a small destroyer.
Experiment: <https://youtu.be/ev4lW0wbnX8?t=1245> (German audio track, machine translated subtitles in English available)
The question is whether this settles the argument or stokes its flames.